Honda does have their own special coolant (its a darker emerald green, not the normal neon green, or in the case of newer hondas its light blue type II coolant) that said regular 50/50 Prestone will work fine.

The 2005 Honda Civic uses ZerexBlue 50/50 antifreeze engine coolant. It has a capacity of about 1.3 gallons.

Abs (anti-lock braking system) is standard on the 2005 Honda Civic EX, SI, and hybrid; and optional on the Civic GX.

Prestone 50/50 Prediluted Antifreeze/Coolant for Honda/Nissan vehicles is compatible with ANY antifreeze/coolant, regardless of color, and can be used in ALL makes and models of cars and light duty trucks. Product Features: Top-off a vehicle’s cooling system with Prestone 50/50 for Honda/Nissan vehicles.

Typically, you should have your 2020 Honda Civic coolant flush completed every 30,000 miles or every two years.

It’s a closed system, you should never have to add coolant unless there is a leak. Look at the coolant overflow reservoir and if its betweem the full and add marks, you don’t have to do anything. If you have to add to it more than once, then you ‘d best get the leak checked.

Remove the radiator cap and pour distilled water into the radiator until full. Replace the cap, then start up the vehicle and let it run for 10 to 15 minutes. This will work the distilled water into the engine, flushing out any loose debris or corrosion along with the last of the old antifreeze.

Contaminated coolant: A bad head gasket or cracked cylinder head can allow oil and coolant to mix, resulting in sludge. In vehicles with automatic transmissions, the engine-cooling system also cools the transmission. A breach in the system can contaminate coolant with transmission fluid.

Why is my coolant brown and thick? That rust gives old coolant its orange-brown color. Oil-colored, creamy, very thick coolant might mean serious problems, including a cracked block or blown head gasket. Thick coolant can also occur because or the prior use of store-bought radiator leak stopper additive.